II. Taxonomy

Anoles belong to the large, iguanine family Polychrotidae, characterized by lamellae on the underside of their toes, along with sharp claws, allowing them to deftly climb most horizontal and vertical surfaces (even upside-down), including branches, ceilings and glass. Anoles also have very well-developed and often brightly coloured dewlaps, used for communication between other anoles.

There are two described subspecies of Anolis carolinensis, the Northern A. c. carolinensis (Voigt 1832), and Southern A. c. seminolus (Vance 1991). The difference between the two is that A. c. seminolus has a green dewlap, while A. c. carolinensis has the characteristic pink or bright red dewlap. The latter is more common in the pet trade.


III. Description

The Green Anole is a small lizard with a long, triangular head, an STL of about 13-20 cm (5-8"). The belly is white, except for the bright pinkish-red dewlap on the throat, which it can extend when defending its territory or when a male is courting a female. The rest of the lizard can be coloured between lime green and brown, and some specimens have blue eyelids and white flecks randomly arranged on the body. A white line is observed on the back of females and sexually immature males. Many mature males will have brown-orange splotches on their hind legs, and typically have larger and brighter dewlaps than females.

IV. Behaviour

This diurnal species is semi-arboreal, spending most of its time in the higher spots of the enclosure. They will usually only drop to the ground when feeding or fleeing a perceived threat. An anole that refuses to climb is probably very ill. They are normally bright, alert and wary.

Like most iguanines, anoles are visually-oriented lizards. They use a series of body movements and displays to communicate with each other, such as head bobs, pushups, and displaying the dewlap. The dewlap is a large, brightly-coloured flap of skin on the throat that extends down to the anole's chest. This skin can be stretched out by an erected rod of cartilage. These displays are used to warn strange lizards that enter the anole's territory, or by males courting females.

This species is generally flighty regarding animals larger than itself (including humans); rarely will you find a specimen that allows it to be held. Typically, if the anole allows itself to be held without trying to escape, it is a very sick lizard.

Like most lizards, anoles can autotomize their tail if they feel threatened. This defense mechanism, called caudal autotomy, occurs as a sort of "last ditch" effort for the lizard to escape a predator. Its tail breaks off, and the severed piece proceeds to twitch for several minutes afterwards (due to excited nerves left in the tail). This is supposed to distract the predator while the lizard escapes. The tail can regenerate after time, however the re-grown portion of the tail will not be the same colour or have the same texture as the original tail. Regenerating a tail takes a lot of energy from the animal, as well- the animal will not grow larger until the tail is complete.

These lizards' claim to fame is their uncanny ability to quickly change from green to brown. This colour change is involuntary, but it is important to understand why it occurs. A happy, healthy Green Anole will be bright, lime green. They turn brown when they are stressed or too cool, but an anole that is continually brown is probably very stressed, ill or has no environmental means of warming up to a correct temperature. This colour changing mechanism is caused by layers of coloured cells, called chromatophores, in the skin. The topmost layer consists of xanthophores that contain pteridine and carotenoid inclusions, which give a greenish-yellow colour to the skin. Below this layer are iridophores, which are reflective and somewhat iridescent. Below the iridophores are melanophores, which containing melanin, a dark brown-black pigment. The migration of these dark melanophores above the xanthophore layer causes the change from green to brown. Melanophore migration occurs in response to hormones such as melanophore stimulating hormone (MSH) and norepinephrine (a hormone related to stress, among other physiological processes). It is also interesting to note that the cream-coloured belly region possesses few xanthophores. The dewlap, which is bright red, contains many iridophores, a few melanophores and many erythrophores, which are red chromatophores. (Alexander and Fahrenbach, 1969; Taylor and Hadley, 1970)

V. Diet

These lizards will thrive on a varied diet of invertebrates. Crickets, cockroaches, superworms and mealworms should be part of the diet to provide roughage, and adding soft prey like small hornworms, butterworms, and silk worms adds more nutritional variety. All prey should be gut-loaded on a nutritious diet 24-36 hours before being fed to the lizards. This is to ensure that the prey you are feeding contains a variety of nutrients, as most prey is poorly fed at the pet store. Fatty prey like wax worms are nice supplements, but because of their high fat content they should be fed sparingly. Prey variety is the key to good health. Do not limit your anole's diet to just one or two different types of prey.

Some individuals will also take bits of brightly-coloured fruits and vegetables (as a supplement to their insect diet), such as romaine lettuce, carrot, berries, and fruit baby foods. Slice or shred them into very small pieces (unnecessary for baby food), and place into a small dish where the lizard can easily see and reach it. Place the baby food in a small dish like other vegetables or fruits. Ensure that the dish is kept clean. It is possible to mix powdered calcium supplement into the baby food, and considering the poor calcium content of most vegetation this is a good idea to counteract an imbalance of calcium to phosphorus in the meal. Plant-eating anoles seem to be the exception rather than the rule, and plants should by no means be a large part of the diet, but a small supplement.

Young anoles should have food available daily (preferably confined to a dish so that the prey is easy to find). Adults can be fed every 2-5 days, as much as they will eat in about 10 minutes is a good way to find out how much your lizard will normally take. Remove uneaten food from the enclosure, as invertebrates can chew on sleeping lizards.

Dietary supplement powders are a controversial topic as we are uncertain of exactly how much is needed. We cannot possibly provide the same type of nutrition that these animals have in the wild, so their use is not unfounded. Vitamin and minerals overdoses are possible, so they should be used sparingly, and gut-loading should never be replaced by supplements. Because most invertebrate prey has an inverse calcium to phosphorus ratio, consider dusting most invertebrate prey with calcium powder. Multivitamin and mineral supplements can be used less often. Gravid females should be provided more calcium in their diet to make up for calcium lost to eggshell and yolk production. My personal supplementing schedule for all of my insectivorous herps includes calcium every 1-2 meals, and a multivitamin and mineral supplement every 4-5 meals.

VI. Housing

Size and build: Many older sources suggest that two adult anoles can be kept in a 38 L (10-gallon) aquarium, but this is not ideal as it can be very stressful to the lizards. Anoles are very territorial, so a much larger enclosure would be needed to cohabitate multiple lizards. One anole may be kept in a 38 litre/10 gallon enclosure, but add 11-15 L more (3-5 gallons) for each other individual, and do not house males together. If you are planning on introducing several lizards to the same aquarium, do it at the same time so that they can "decide" on territories; lizards added gradually may be seen as intruders. Remember that a sparsely inhabited enclosure is better than a crowded one. A single anole will be healthier alone than with cagemates.

On a related note, mixing species is not recommended. Particularly, Green Anoles also should not be housed with Brown Anoles, Norops sagrei. This is a common display in pet stores, but Brown Anoles are a much more aggressive species and tend to stress out greens and outcompete them for food, heat and hides. Wild populations of greens are actually suffering because of introduced browns.

The enclosure may be screen, wooden or glass, as long as humidity and temperature requirements are met. Completely transparent enclosures are discouraged, since these are prey animals and some security should be provided by covering several sides of the enclosure.

If using an aquarium, the lid should not be an aquarium cover intended for fish. Either buy a screen lid to fit the top or make your own. A screen portion is safe to put lights over and allows ventilation. The lid must be too heavy for the lizards to move.

An enclosure setup for a Green Anole. The plants should grow in more to offer more hiding places for the lizards. Another anole setup. These plants need to be pruned. Both of these enclosures are horizontally-oriented, more vertical space is ideal.

Cage furniture: Vertical climbing space and plenty of plant cover are key with anoles. These lizards live in forest habitats, and this should be simulated in captivity. Branches placed vertically, diagonally and horizontally provide climbing and resting spots. Live or fake plants may be used. Fake plants are less work to maintain than live plants, but live plants provide more humid microhabitats and can help to raise relative humidity. Tough and hardy plants that appreciate warm, humid conditions like pothos, philodendrons, dracaenae (like the Madagascar dragon tree and corn plant dracaena), hibiscus, some bromeliads, spider plants and sansvierias (snake plants) have been used with success in anole enclosures. All plants to be used in the enclosure should be repotted into a sterile, plain potting soil free of fertilizers, pesticides, vermiculite and perlite (small Styrofoam balls). The entire plant should be rinsed several times in lukewarm water to remove any pesticide residue from the nursery. Inspect the plants before purchase for pests like slugs, aphids and others. Once in the enclosure, maintain the plants according to their appropriate needs. See Plants for the Tropical Terrarium for more information. Substrate: As substrate, plain potting earth is relatively safe, simple and cheap. Be sure to select soil with no additives such as fertilizers, vermiculite or perlite. Appropriate forest soil mixes including soil, woodchips, sand and decomposing leaves are also suitable. Substrate consisting of loose chunks of material such as woodchips, crushed walnut shell and crushed corncob should be avoided, as these are generally unsuitable for lizards for various reasons. Simple sheet substrates like paper towels or newsprint are suitable for a temporary enclosure (such as a quarantine or hospital cage), however natural substrates that are properly maintained will help raise humidity and preserve a natural atmostphere.

VII. Water

Wild anoles drink from water droplets on vegetation. Water should be misted in the enclosure, on the leaves of the artificial or live plants and enclosure walls at least once a day. A spray bottle or automatic misting equipment will both work equally well.

A water dish is not necessary for drinking, but a wide, shallow water dish can help raise humidity in the enclosure. The dish should be cleaned regularly. These lizards can sometimes learn to drink out of a pool of water, but still mist the enclosure daily to ensure that the lizard is getting enough to drink.

VIII. Heating

These lizards are heliothermic, meaning they warm themselves by basking in sunlight. To accomodate this, a basking spot using a radiant heat source such as an incandescent light bulb must be provided.

Daytime temperatures should range from 32 °C (90 °F) at the basking spot to 22 °C (75 °F) at the cool region of the enclosure.

At night the entire enclosure should fall no lower than 18 °C (65 °F). At night, no heating may be necessary if the room does not get too cool, or if the enclosure is well-insulated. If a nighttime heat source is required, one that produces no visible light, such as a ceramic heat emitter or an infrared incandescent may be used.

IX. Humidity

The relative humidity of the enclosure should generally range between 50-60%. Using a natural soil substrate, adding live plants and a wide, shallow water dish will help maintain humidity. Various humid microhabitats up to 100% humidity can be provided by using live plants, slabs of bark and moist sphagnum moss. The enclosure humidity will also increase periodically when it is misted.


X. Lighting

Light quality is often overlooked in reptiles and amphibians. Broad-spectrum lighting (including UV-A and UV-B wavelengths, which are naturally found in sunlight) is suggested for these lizards. Most domestic lightbulbs produce these wavelengths in negligable quantities, or not at all. Specially made bulbs for use with herps and/or birds are required, and they must be replaced every 6-10 months depending on their usage and the manufacturer's suggestions. These bulbs should not be placed further than 38 cm (15")from the closest basking spot, as the amount of UV reaching the animal decreases significantly with distance. Plastic and glass completely filter UV, and mesh or screen filters a noticeable amount.

Ultraviolet B is necessary for vitamin D metabolism in these lizards. Vitamin D3 is created in the skin, and through different processes is eventually transformed into a hormone that allows the body to absorb calcium from the diet. Neglecting to provide UV-B lighting will result in calcium deficiency-related problems, often called metabolic bone diseases.

A source of light that provides UV-A is necessary because of the behavioural implications that UV-A has. Ultraviolet A is important when considering reptile vision as they can see certain wavelengths that we cannot. Not providing this wavelength has behavioural implications as it may be rendering them colour-blind to an extent.

Provide a photoperiod of 12-14 hours, varying with the seasons. A proper day/night cycle can be achieved by using an electrical timer.

XI. Sexing

Sexing anoles is not difficult. Males are typically larger-bodied than females, particularly their heads. Males will sometimes develop small crests along their neck and back, and have a much brighter dewlap than females. Males also have a distinct hemipenile bulge, which can be seen at the base of the tail just after the cloaca (vent). Males also possess post-cloacal pores. Females will retain a white stripe down the back, although some males also keep this feature until adulthood.

XII. Health

Proper husbandry is the key to good health in all reptiles. If you provide good basic care, then you will avoid the vast majority of potential health problems that reptiles can encounter in captivity.

Because Green Anoles are virtually all wild caught, they are undoubtedbly parasitized. The process of being captured is very stressful, and this stress can afflict the immune system and allow any normally harmless parasites to become disease-causing. A fecal exam should be performed by an experienced reptile vet to determine if antiparasitic medications are needed to prevent any parasite-related health problems.

Anorexia is a common problem in captive anoles, and is often attributable to poor environmental conditions (too hot, too cold or too stressful) or a heavy parasite load.

When in doubt about a health issue with your pet, do not hesitate to contact a knowledgeable reptile and amphibian veterinarian. To find a vet in your area, see the directory at the Association of Reptile and Amphibian Veterinarians website.

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